Use of electrostatic charge to repel substances from surfaces during cleaning

ABSTRACT

POSITIVELY CHARGED DIRT PARTICLES ARE CLEANED FROM THE SURFACE OF A VEHICLE BODY BY POSITIVELY CHARGING THE SURFACE TO ELECTRICALLY REPEL THE PARTICLES, THE SURFACE THEN BEING WASHED WHILE THE CHARGE THEREON IS POSITIVE. A CAPACITOR IS FORMED BY THE SURFACE AND A CONDUCTIVE PLATE OR PLATES WHICH ARE SPACED THEREFROM AND CONNECTED TO THE NEGATIVE OUTPUT TERMINAL OF A SOURCE OF DIRECT VOLTAGE. THE VEHICLE BODY OR FRAME IS CONNECTED TO THE POSITIVE TERMINAL TO ESTABLISH AN ELECTROSTATIC FIELD BETWEEN THE SURFACE AND THE PLATES AND EFFECT THE POSITIVE CHARGING OF THE SURFACE.

United States Patent Ofice 3,684,575 Patented Aug. 15, 1972 USE OF ELECTROSTATIC CHARGE T REPEL SUBSTANCES FROM SURFACES DURING CLEANING Arthur S. King, Prairie Village, Kans. (1710 Baltimore Ave., Kansas City, Mo. 64105) No Drawing. .Filed Oct. 22, 1969, Ser. No. 868,604

Int. Cl. B08b 7/04 U.S. Cl. 134-1 6 Claims ABSTRACT OF THE DISCLOSURE Positively charged dirt particles are cleaned from the surface of a vehicle body by positively charging the surface to electrically repel the particles, the surface then being washed while the charge thereon is positive. A capacitor is formed by the surface and a conductive plate or plates which are spaced therefrom and connected to the negative output terminal of a source of direct voltage. The vehicle body or frame is connected to the positive terminal to establish an electrostatic field between the surface and the plates and eflfect the positive charging of the surface.

This invention relates to a method of cleaning dirt from a conductive surface through the use of a electro static charge that repels the dirt particles.

The frame and body of an automobile or truck carry a negative electrostatic charge. Even vehicles having positive ground electrical systems assume a negative charge when not in operation. This phenomenon creates a problem in washing the vehicle since the dirt that collects on the exterior body surface consists predominantly of mineral substances in positive ion form. Accordingly, the positively charged dirt is attracted and held on the negatively charged surface, rendering it difficult to break the electrostatic bond except by vigorous scrubbing.

It is, therefore, an important object of the present invention to provide a method of releasing dirt or other materials electrostatically held on a surface to be cleaned, thereby permitting the dirt to be readily removed from the surface by conventional techniques.

Another important object of the invention is to provide a method of repelling charged dirt particles or other materials from a surface to be cleaned.

Still another important object of this invention is to provide a method of electrically charging a conductive surface to repel dirt particles or other materials thereon carrying a charge of the same sign, in order to further provide an improved method of cleaning such surface.

Yet another important object is to provide a method of cleaning vehicle bodies that carry a normally negative electrostatic charge, wherein such method includes reversing the charge to repel ionic mineral substances or other positively charged materials adhered to the body surface.

Other aims and objectives will become clear as the detailed description of the present invention proceeds.

The negative electrostatic charge assumed by the frame and body of an automotive vehicle inhibits the cleaning of the exterior body surface since, as mentioned above, the dirt that collects on the surface consists predominantly of mineral substances in positive ion form. The attraction of unlike charges causes the dirt particles to adhere to the surface by an electrostatic bond as well as the physical adhesion that is readily broken by a suitable solvent, such as water or a combination of water and detergent in usual washing techniques. Being incapable of breaking the elec trostatic bond except, of course, by actual physical displacement of the dirt particles or chemical interaction therewith, substantial scrubbing and/ or the use of strong detergents are oftentimes required for efficient and thorough cleaning.

In the present invention the negative charge of the vehicle body is reversed in order to repel the positively charged dirt particles and thereby break the electrostatic bond between such particles and the surface of the vehicle body. This not only eliminates the electrostatic forces of adhesion, but also repels the dirt particles from the surface to be cleaned so that a water spray is effective in quickly flushing the dirt from the surface without the need for scrubbing under ordinary conditions.

The facility utilized in the practice of the present invention is preferably enclosed and may be provided with a means of automatically subjecting a vehicle to a water spray over its entire outer surface. Such installations are commonplace and may be of the type where the vehicle is slowly advanced through the water spray or, alternative- 1y, maintained stationary through the water spray or, alternatively, maintained stationary while subjected to a plurality of jets that strike the body surface. The water spray may also be applied to the body manually. In any event, it should be understood that the particular means of applying the water spray to the body surface is not critical to the operability of the present invention, as will become apparent.

One or more plate electrodes are positioned in spaced relationship to the body surface at the facility and are connected to the negative output terminal of a source of direct voltage. The positive terminal is connected to the vehicle body, such as through the use of a lead that is electrically connected to the bumper of the vehicle. If desired, a contact arm (connected to the positive terminal) could be disposed in the path of travel of the vehicle entering the facility, and the vehicle driven to a position where the arm engages the front or rear bumper. Here again, the exact means of connecting the car body to the positive potential is not important but would be dictated by considerations of expediency for a particular washing installation.

The electrodes should be as close to the surface to be cleaned as is convenient and still permit the free passage of a water spray. The electrode or electrodes and the metallic surface of the body form a capacitive configuration which may take a variety of forms. For example, a pair of metal plates may be disposed on opposite sides of the vehicle and oriented in parallel vertical planes, the height of the plates being at least as great as the height of vehicles to be accommodated and the length thereof equal to the maximum vehicle length. An overhead plate could also be employed in addition to the side plates. As a further example, a single electrode may be formed by a single metallic plate of inverted, trough shape to form a tunnel into which the vehicle is driven. Whether single or multiple electrodes are utilized, allare connected to the negative terminal of the voltage source so that the electrostatic field of the capacitor is between the outer, metallic surface and the vehicle body and the adjacent electrode or electrodes.

The capacitive configuration serves to charge the vehicle body positive so that the metallic surface thereof becomes the positively charged plate of a capacitor, thereby repelling the positive ionic substances adhered thereto which are to be removed. The surface is subjected to the water spray while it is maintained at the positive potential, thus the collected dirt particles and other materials are readily washed away.

The voltage utilized will depend upon the capacitance of the configuration since the transfer of charge in a capacitor is directly dependent upon both the capacitance thereof and the potential difference between its oppositely charged plates. High voltages on the order of several thousand volts are preferred, the only limitation being considerations of safety. In this respect, the power source may utilize a 110 volt alternating current supply with a step-up transformer to provide the needed voltage level. In the rectification and filter circuits, current limiting should be employed to prevent the creation of a hazard. It should be understood that current output is of little significance since the function of the power source and the capacitive configuration is to reverse the charge on the surface of the vehicle body by placing a positive static charge thereon.

Due to the presence of wash water and as an additional safety precaution, the negative plate electrodes should be encapsulated in an insulating covering as well as mounted on insulated supports. The tires of the vehicle provide adequate isolation of the body from ground.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A method of cleaning charged materials from a conductive surface having an electrostatic charge that attracts and adheres said materials thereto, said method comprising the steps of:

I reversing the charge on said surface to electrically repel said materials; and

removing said materials from said surface while said charge is reversed,

said step of reversing said charge including the substeps of:

providing an electrode in spaced relationship to said surface to present a capacitive configuration, and

establishing a potential difference between said surface and said electrode to create an electrostatic field therebetween and charge the surface oppositely in sign,

said step of removing said materials including washing the materials from said surface.

2. A method of cleaning positively charged materials from a conductive surface of a vehicle body, wherein said 3. The method as claimed in claim 2, wherein the step of positively charging said surface includes the substeps surface has a normally negative electrostatic charge that providing an electrode in spaced relationship to said surface to present a capacitive configuration; and applying positive and negative electrical potential to said surface and said electrode respectively to thereby establish an electrostatic field therebetween and effect the positive charging of the surface.

4. The method as claimed in claim 3, wherein the step of removing said materials includes washing the materials from said surface.

5. The method as claimed in claim 2, wherein the step of positively charging said surface includes the substeps of:

providing an electrode in spaced relationship to said surface to present a capacitive configuration; and electrically coupling said surface and said electrode to positive and negative output terminals respectively of a source of direct potential, thereby establishing an electrostatic field between the surface and the electrode and effecting the positive charging of the surface.

6. The method as claimed in claim 5, wherein the substep of electrically coupling said surface and said electrode to said terminals includes connecting said vehicle body to said positive terminal.

References Cited UNITED STATES PATENTS MORRIS O. WOLK, Primary Examiner D. G. MILLMAN, Assistant Examiner US. Cl. X.R. 1s 1.s, Dig. 2 

